Wealth shocks and cognitive function in later life
Authors: Xiaoying Zheng, Yanan Luo
Journal: The Lancet Healthy Longevity (2023)

Cognitive impairments can have detrimental effects on various aspects of an individual's life, including reduced social interaction, a diminished sense of purpose, difficulties in performing daily activities, and decreased resilience in recovering from illness or injury.1Hendrie HC Albert MS Butters MA et al.The NIH Cognitive and Emotional Health Project. Report of the Critical Evaluation Study Committee.Alzheimers Dement. 2006; 2: 12-32Crossref PubMed Scopus (243) Google Scholar Although cognitive decline is an inevitable part of the ageing process, there is still a certain degree of cognitive plasticity in later life. Existing research has shown that modifiable risk factors, such as metabolic diseases, sensory impairments, unhealthy lifestyles, and air pollution, account for 40% of the risk factors for dementia.2Livingston G Huntley J Sommerlad A et al.Dementia prevention, intervention, and care: 2020 report of the Lancet Commission.Lancet. 2020; 396: 413-446Summary Full Text Full Text PDF PubMed Scopus (2948) Google Scholar Therefore, it is important to identify modifiable factors associated with cognitive decline to help maintain cognitive function in later life. A population-based, cross-nationally harmonised, longitudinal study conducted by Tsai-Chin Cho and colleagues,3Cho T-C Yu X Gross AL et al.Negative wealth shocks in later life and subsequent cognitive function in older adults in China, England, Mexico, and the USA, 2012–18: a population-based, cross-nationally harmonised, longitudinal study.Lancet Healthy Longev. 2023; (published online Aug 3.)https://doi.org/10.1016/S2666-7568(23)00113-7Google Scholar published in The Lancet Healthy Longevity, delved into the association between negative wealth shocks experienced in later life and subsequent cognitive function. The findings suggest that negative wealth shocks (defined as a ≥75% loss in wealth or a decline in within-population wealth quintile rank) might be a modifiable risk factor associated with cognitive decline. The study specifically examined the relationship between negative wealth shocks and subsequent cognitive function across four countries (China, England, Mexico, and the USA), highlighting the importance of socioeconomic determinants in studying modifiable factors related to cognitive health. Following the COVID-19 pandemic, global economic growth has sharply declined, contributing to instability and intensifying the health challenges associated with wealth shocks, especially for vulnerable populations such as older adults and individuals excluded from public policies.4UN Department of Economic and Social AffairsWorld economic situation and prospects. United Nations, January 13, 2022https://www.un.org/development/desa/dpad/publication/world-economic-situation-and-prospects-2022/Date accessed: July 4, 2023Google Scholar Cho and colleagues3Cho T-C Yu X Gross AL et al.Negative wealth shocks in later life and subsequent cognitive function in older adults in China, England, Mexico, and the USA, 2012–18: a population-based, cross-nationally harmonised, longitudinal study.Lancet Healthy Longev. 2023; (published online Aug 3.)https://doi.org/10.1016/S2666-7568(23)00113-7Google Scholar observed a significant correlation between wealth shocks in later life and subsequent decline in cognitive function in older adults in China and the USA, but not in Mexico and England. Disparities in government policies and social safety nets for older adults were suggested to be the potential reasons for this variation. For instance, an established public health-care and welfare system in England and a non-contributory pension programme for individuals aged 70 years and older in Mexico (from 2007 onwards) could have potentially reduced the risks associated with wealth shocks and mitigated their adverse effects on cognitive health. The association between wealth shocks and cognitive health can be regarded as a manifestation of the cumulative impact of accumulated risk factors on health outcomes throughout the life course. Existing evidence highlights the cumulative negative effects of adverse life events, such as job losses and exposure to natural disasters during the prenatal period and early years, which contribute to an increased risk of cognitive impairment or mental health problems in later life.5Guo C Chen G He P Zhang L Zheng X Risk of cognitive impairment in children after maternal exposure to the 1998 Yangtze River flood during pregnancy: analysis of data from China's second National Sample Survey on Disability.Lancet Planet Health. 2020; 4: e522-e529Summary Full Text Full Text PDF PubMed Google Scholar, 6Luo Y Wang Y Hong C He P Zheng X The shattered "Iron Rice Bowl": effects of Chinese state-owned enterprise reform on depressive symptoms in later life.Soc Psychiatry Psychiatr Epidemiol. 2023; (published online March 28.)https://doi.org/10.1007/s00127-023-02437-9Crossref PubMed Scopus (0) Google Scholar Wealth shocks can serve as important intermediary pathways linking these major adverse life events with cognitive health. On one hand, wealth shocks resulting from job loss or natural disasters might diminish opportunities for engaging in cognitively stimulating activities, thereby reducing cognitive reserves and resilience to cognitive decline.7Stern Y Alexander GE Prohovnik I et al.Relationship between lifetime occupation and parietal flow: implications for a reserve against Alzheimer's disease pathology.Neurology. 1995; 45: 55-60Crossref PubMed Google Scholar On the other hand, wealth shocks themselves can induce stress and psychological issues such as depression, which can impair information processing and subsequently lead to a decline in cognitive performance.8McEwen BS Stellar E Stress and the individual. Mechanisms leading to disease.Arch Intern Med. 1993; 153: 2093-2101Crossref PubMed Google Scholar However, when examining the impact of cumulative exposure factors such as wealth shocks on health, the most important challenge lies in how to control for confounding factors that can arise throughout the life course. Common approaches to detect these effects include conducting natural experiments or randomised controlled trials to identify casual relationships. Additionally, the establishment of long-term cohort surveys and the development of new analytical techniques to assess the effect of cumulative risks are future directions that require substantial efforts. It is worth noting that some low-income and middle-income countries have already taken steps in this direction. For instance, China, as a populous country undergoing rapid social transformation, is establishing a population ageing disability data repository that encompasses the modules of heterogeneous fusion data warehouse, dynamic intelligent risk analysis, and sensitive information tracing.9Luo Y Chen W Wang Y et al.To design an intelligent analysis platform for the disabled population data.Wei Sheng Yan Jiu. 2021; 50 (in Chinese).: 660-664PubMed Google Scholar The association between negative wealth shocks and cognitive function, specifically the causal relationship and underlying mechanisms, should be further investigated as this information can serve as a foundation for formulating relevant policies that aim to safeguard cognitive health and promote healthy ageing amidst wealth shocks. The study by Cho and colleagues3Cho T-C Yu X Gross AL et al.Negative wealth shocks in later life and subsequent cognitive function in older adults in China, England, Mexico, and the USA, 2012–18: a population-based, cross-nationally harmonised, longitudinal study.Lancet Healthy Longev. 2023; (published online Aug 3.)https://doi.org/10.1016/S2666-7568(23)00113-7Google Scholar highlights the roles of government policies and social safety nets in mitigating wealth shocks, as well as the importance of cognitive health monitoring and psychological counselling to individuals affected by such shocks, which are crucial for supporting cognitive function and ensuring overall wellbeing. We declare no competing interests. Negative wealth shocks in later life and subsequent cognitive function in older adults in China, England, Mexico, and the USA, 2012–18: a population-based, cross-nationally harmonised, longitudinal studyThe impact of wealth shocks in later life on subsequent lower level of cognitive function of older adults in China, England, Mexico, and the USA differed across macro-level socioeconomic structures. These findings suggest that government policies and social safety nets in countries with different levels of economic development might have a role in protecting older adults from adverse health effects of wealth losses in later life. Full-Text PDF Open Access